A nationwide police operation has seized more than $10 million worth of illegal drugs posted through international mail, some of which were destined for Schoolies Week on the Gold Coast.

The blitz involving Customs, Australian Federal Police (AFP) and state and territory police netted 38 kilograms of drugs including heroin, cocaine, methamphetamines, MDMA, cannabis, steroids and the drug known as meow.

In Sydney, drugs were detected in a wedding dress and a piano. In Perth some were hidden in bicycle parts, while in Brisbane some were concealed in a carton of soap.

"The important thing to remember here is this is 38 kilos of drugs that our kids won't be ingesting at Schoolies next week, won't be being used over the holiday period," he said.

"And if you are involved in that drug trade and you're bringing in large amounts of drugs through yachts or smaller amounts through parcels, posts, there's a very good chance we'll be coming and knocking on your door."

A number of people have been arrested, but police say inquiries are still ongoing.

Police say these types of drug busts are just as important as the bigger ones - police recently seized 464kg of cocaine, one of Australia's largest ever drug hauls, from a yacht off Brisbane.